ABSTRACT Support is requested for a Keystone Symposia conference entitled B Cell Renaissance: Epigenetics, Regulation and Immunotherapy, organized by Drs. Paolo Casali, Nicole Baumgarth, Meinrad Busslinger and Elizabeth Leadbetter. The conference will be held in Banff, Alberta Canada from March 1-5, 2019. This conference will bring together experts in B cell biology to discuss the most recent advances in B cell research from initial development, through maturation, including effector or memory development, until terminal differentiation. The results of these recent B cells studies are guiding researchers to become more appreciative of the importance of the molecular changes, including epigenetic marks, modifications and factors that control and modulate B cell development and differentiation as well as the regulatory forces which influence functional paths of B cells. The complexities of B cell differentiation pathways through germinal centers and extra- follicular foci in primary lymphoid organs, in addition to novel interactions in diverse secondary lymphoid tissues, are also under intense study in both mice and humans. The interactions of B cells with lymphoid cells, non-lymphoid cells, and secreted factors in a myriad of environments will be covered in conference sessions. This will help elucidate the numerous factors which influence and ultimately dictate the contribution of each unique B cell subset to homeostasis, immune defense or immunopathology. Understanding the drivers which influence B cell differentiation and function will enable precise harnessing of these key elements to optimize the immuno-therapeutic effect of B cells and their antibodies in autoimmune disease, infection, and cancer.